To meet the power management requirements of modern computers it may be common for idle cores of a processor to be completely turned off to save power. Powering off a core, however, eventually requires that the core be re-initialized similar to the way it was initialized at boot time. In some processors, an assist co-processor called a power-on reset (POR) engine may be used for re-initializing the cores of the system. The POR engine may consume very little energy in comparison to the cores of the computer system. The POR engine may request to bring a core back online by executing instructions from a re-initialization program stored in main memory that instructs the POR on how to properly re-initialize the core and introduce it back into a processing fabric.